No, fermentation is a process of enzymatic transformation.

Black tea is fermented, for example. No need for bacteria.

I have to disagree: black tea only had an oxidation while fermented tea had an oxidation plus a fermentation by microbial activity: https://en.m.wikipedia.org/wiki/Fermented_tea

The term "fermentation" is very often used buy common language to describe both fungic and microbial activity.